Fall Issue 2021 - 91

Meeting City Focus
In Cook County, where Chicago is located,
the Metropolitan Water Reclamation District of
Greater Chicago has turned to an additional
solution. Fourteen miles (23 km) outside Chicago
in the village of Harwood Heights, for example,
the district has helped fund the construction of
several green alleys, with permeable pavement
that allows rainwater to seep through spaces
into the ground instead of staying on top, as it
would with conventional asphalt.
Green infrastructure, as such projects are called,
aims to capture and store water close to where
it falls. Instead of massive pipes, tanks, tunnels,
and reservoirs, elements of green infrastructure are
smaller and more numerous, scattered across an
urban area. In addition to permeable pavement,
such infrastructure ranges in form from rain gardens
and green rooftops to bioswales-drainage
channels planted with vegetation.
While green infrastructure is not a completely
new idea-the city of Chicago, for example, has
been repaving alleys with permeable surfaces
for years-the metropolitan water district is
working to expand its reach across suburban
areas that use its sewer system as well. The
district provides $5 million each year in competitive
grants to local governments to build green
infrastructure, according to its annual budget
documents. The district has completed or is currently
planning 60 projects, including 21 to be
completed this year, says Allison Fore, a public
and intergovernmental affairs officer with the
district. In addition, the district partners with the
Chicago Public Schools, the city's Department
of Water Management, and other groups on the
Space to Grow program, which has renovated 25
local schoolyards and added permeable surfaces
to manage rainfall.
Other U.S. cities are also increasingly turning
to green infrastructure to augment conventional
stormwater systems, often by funding neighborhood
and environmental groups, as well as
requiring developers to include it in projects.
Though implementing smaller, distributed
green infrastructure projects costs far less than
building gray infrastructure, it requires creative
thinking and innovative funding mechanisms.
But proponents note that green infrastructure
provides benefits that go beyond controlling
stormwater. Sites devoted to infrastructure can
double as recreational space or traffic barriers,
or help improve an area's appearance. Maintaining
green infrastructure can provide jobs for
residents and promote economic equity in disadvantaged
neighborhoods, as well as improve
the quality of life there.
Emulating Nature to Improve
Resilience
" We have to figure out how to reproduce what
nature did for millennia, " says Williams-Clark.
" We're not going to be able to build enough
pipes, tanks, and tunnels to get us out of this. "
The stormwater problems that cities face
are tied to changes in climate that have led to
increased rainfall in some regions. In a 2019 article
for The Conversation website, Shuang-Ye Wu,
an associate professor of geology at the University
of Dayton who analyzed historical climate
data from 1951 to 2013, reported that mean precipitation
in the Midwest has been increasing by
2.1 percent per decade. Half of the increase has
been caused by more frequent storms, and the
rest is attributable to increased storm intensity.
According to Wu's modeling, rainfall across the
Midwest by midcentury is likely to increase by 8
percent from 1970-2000 levels.
Often, much of the harm caused by urban
flooding is suffered by less affluent and minority
neighborhoods. A Center for Neighborhood
Technology study of $400 million in insurance
payments made for flood damage in Chicago
between 2007 and 2016 found that 75 percent
of the claims were paid in a handful of zip
codes where 93 percent of the residents were
people of color and a quarter of households had
incomes below the federal poverty line.
" Generally, we should enhance the capacity
of our infrastructure and strengthen our potential
for resilience, " says David Strifling, director of
Marquette University Law School's Water Law
and Policy Initiative. " Green infrastructure can be
one piece of that puzzle. When properly installed
and maintained, it reduces and slows stormwater
runoff, in turn helping to manage localized
flooding. "
In addition, he says, " it replenishes groundwater
reserves, prevents erosion, reduces energy
use at treatment facilities, lowers the temperature
in urban heat islands, and reduces energy
use within individual buildings through the cooling
effects of green roofs and vegetative cover. "
Moriah Gelder, a civil engineer for the Chicago
area's metropolitan water district, says the green
infrastructure provides two types of protection: in
addition to reducing flooding in the immediate
area, it also decreases the stormwater going into
a combined sewer system, which can prevent
overflows and flooding elsewhere in the system.
" The size, design, and location [of green
infrastructure] all factor into how much flooding
protection the installation can provide to nearby
structures, " she says. " For example, if there is a
street that often floods during a rainstorm, installing
a roadside rain garden and curb cuts to allow
the stormwater on the street to flow into the rain
garden and soak into the ground is an ideal use
of green infrastructure. Flooding on the street often
means that the sewer system is full, so any stormwater
we can redirect away from the sewer system
will help prevent combined sewer overflows and
backups of combined sewers into basements. "
Gelder notes that buildings also can be
designed to more effectively use the green infrastructure
around them. " A design decision such
as raising the underdrain will allow more water
to soak into the ground beneath a GI [green
infrastructure] installation rather than be slowly
discharged into the connecting sewer, " she says.
That eliminates the discharge from ever reaching
the sewer system, rather than just holding it
back and releasing it slowly.
Green Infrastructure Innovation
Besides Chicago, other cities are adding green
infrastructure to their stormwater management
strategies.
In Detroit, the Detroit Water and Sewerage
Department plans to spend $50 million by
2029 to build green infrastructure projects. The
agency already has completed 12 projects with
the capacity to manage 61 million gallons (231
million liters) of stormwater. Detroit's expanse of
vacant lots-40 percent of the city's 141 square
miles (365 sq km) is owned or controlled by the
government-offers officials plenty of locations
to choose from.
One recent project in Detroit involved an $8.6
million transformation of traffic medians along
Oakman Boulevard, which combines vegetation
with an underground storage tank to manage 37
million gallons (140 million liters) of stormwater
each year.
FALL 20 21
URBAN LAND
91
Fall Issue 2021

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